The present disclosure relates to a method of forming nanorods and a method of manufacturing a semiconductor element.
In the field of semiconductor elements such as electronic devices and optical devices, due to development of semiconductor materials such as nitride semiconductors and progress in manufacturing technology, high quality semiconductor elements have been realized. In recent years, efforts to achieve further miniaturization and higher efficiency have been made by, for example, using nanorods having a diameter or width of 100 nm or less, which allows for improving internal quantum efficiency due to quantum confinement effects and strain relaxation effects.
Methods of forming the nanorods are roughly classified into a bottom-up method employing crystal growth and a top-down method employing etching. Japanese Patent Publication No. 2008-544567 disclose a method of forming nanorods made of GaN in a bottom-up manner. In this method of forming nanorods, lateral growth is suppressed by adjusting crystal growth conditions such as the temperature, pressure, and flow rates of precursors of Ga and N to grow GaN upward. Also, Japanese Patent Publication No. 2014-509075 discloses a top-down method of forming nanorods made of a nitride semiconductor. In this method, nanorods made of a nitride semiconductor are formed by forming a mask in a form of islands on a nitride semiconductor layer and removing a portion of the nitride semiconductor between the islands of the mask. The mask on the nitride semiconductor includes two layers: a nickel layer and a silicon oxide layer.